Enhanced In Vitro Phagocytosis of Different Pathogens by Human Monocytes in the Presence of Antibiotics

Adam, Dieter

doi:10.1007/978-3-642-68670-2_8

Cited by 12 publications

(7 citation statements)

References 20 publications

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“…Similar to our findings, it has previously been reported that treatment with sub-inhibitory concentrations of antibiotics increased phagocytic uptake of Listeria monocytogenes, 20 Staphylococcus aureus, 21 and E. coli 18 by macrophages, but this enhanced phagocytic activity was not due to a change in the macrophages themselves. 20 In addition, ampicillin or erythromycin exposure did not alter phagocytosis of the BioParticles; therefore, the enhanced phagocytosis of the ST-17 strain is likely due to a change in the bacteria rather than a change in the macrophages. Since penicillin treatment reduced the phagocytic capacity of the macrophages, but …”

Section: Discussionsupporting

confidence: 92%

Differing mechanisms of surviving phagosomal stress among group BStreptococcusstrains of varying genotypes

et al. 2016

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Group B Streptococcus (GBS), a leading cause of neonatal sepsis and meningitis, asymptomatically colonizes up to 30% of women and can persistently colonize even after antibiotic treatment. Previous studies have shown that GBS resides inside macrophages, but the mechanism by which it survives remains unknown. Here, we examined the ability of 4 GBS strains to survive inside macrophages and then focused on 2 strains belonging to sequence type (ST)-17 and ST-12, to examine persistence in the presence of antibiotics. A multiple stress medium was also developed using several stressors found in the phagosome to assess the ability of 30 GBS strains to withstand phagosomal stress. The ST-17 strain was more readily phagocytosed and survived intracellularly longer than the ST-12 strain, but the ST-12 strain was tolerant to ampicillin unlike the ST-17 strain. Exposure to sub-inhibitory concentrations of ampicillin and erythromycin increased the level of phagocytosis of the ST-17 strain, but had no effect on the ST-12 strain. In addition, blocking acidification of the phagosome decreased the survival of the ST-17 strain indicating a pHdependent survival mechanism for the ST-17 strain. Congruent with the macrophage experiments, the ST-17 strain had a higher survival rate in the multiple stress medium than the ST-12 strain, and overall, serotype III isolates survived significantly better than other serotypes. These results indicate that diverse GBS strains may use differing mechanisms to persist and that serotype III strains are better able to survive specific stressors inside the phagosome relative to other serotypes.

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Section: Discussionsupporting

confidence: 92%

Differing mechanisms of surviving phagosomal stress among group BStreptococcusstrains of varying genotypes

et al. 2016

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“…Our results were also in accordance with the data presented by Adam et al [1] who incubated mononuclear cells from man with a strain of Listeria monocytogenes together with subinhibitory concentrations of tetra cycline, ampicillin or chloramphenicol. They found an increased cell-bound ra dioactivity with all the drugs tested.…”

Section: Discussionsupporting

confidence: 82%

“…Over the years evidence has been produced indicating that this anti biotic may influence the host defence mech anisms [3-7, 13, 15]. Previous reports on the interaction between tetracyclines and the phagocytic system have presented evi dence for a depressive effect [2,4,6,7,13, 15J or no effect [8,9], Besides the report of Adam et al [1] we have not been able to find any investigation indicating that tetracy clines enhance the phagocytic activity of hu man leukocytes. As our primary studies seem to yield similar results, further investi gations were undertaken.…”

Section: Introductionmentioning

confidence: 97%

Effects of Doxycycline on the Phagocytosis of <sup>32</sup>P-Labelled <i>Escherichia coli</i> by Human Polymorphonuclear Cells

Melby¹,

Midtvedt²

1981

Chemotherapy

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A study on the effect of various concentrations (2–100 μg/ml) of doxycycline on the phagocytic activity of human polymorphonuclear cells was undertaken using a radio-labelled strain of Escherichia coli as test particle. In the presence of 10% normal human serum pretreatment with 50–100 μg/ml resulted in a 50% increase in cell-associated radioactivity. When omitting serum during the ingestion phase, or conducting the ingestion phase at 4°C, the ingestive capability was reduced. 2 μg/ml present during the ingestion together with 10% normal human serum reduced the ingestive capability significantly, whereas the presence of 10 μg/ml exerted no significant effect. By the use of ³Η-labelled doxycycline the drug was shown to be firmly fixed to the leukocyte monolayer.

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“…These effects may be due to perturbation of the outer membrane and a change to serum sensitivity [31]. Antibiotics also may alter lysozyme function [32], antibody and complement [15], or phagocytic ability [11,33,34]. In addition, pretreatment of staphylococci or streptococci with sub-MICs of penicillin facilitates phagocytic ingestion and killing [35,36].…”

Section: Discussionmentioning

confidence: 99%

Intermittent or Continuous Therapy of Experimental Meningitis Due to Streptococcus pneumoniae in Rabbits: Preliminary Observations on the Postantibiotic Effect in Vivo

Sande¹,

Korzeniowski²,

Allegro³

et al. 1981

Clinical Infectious Diseases

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The relative effectiveness of bolus vs. constant intravenous administration of equivalent doses of penicillin G in killing bacteria in vivo was studied in a rabbit model of meningitis due to Streptococcus pneumoniae. Samples of cerebrospinal fluid (CSF) and serum were obtained from 30 rabbits at intervals of~8 hr after treatment for determination of antibiotic concentrations and titers of viable bacteria in the CSF. When penicillin G was given by continuous infusion (105 units/hr after an initial lOS-unit loading dose), concentrations of drug in serum and CSF reached a steady state in 1 hr. With intermittent bolus administration of 4 x 105 units every 4 hr, higher peak and lower trough concentrations were achieved, and these concentrations paralleled those in the CSF. Although an initial acceleration in bactericidal rate was observed with the bolus infusion between the first and second hour of therapy, after the second hour the rate of bacterial killing was identical for the two methods of administration. The duration of therapy required for sterilization of the CSF was dependent only on the bacterial count before treatment and not on the mode of drug administration. The effect of single bolus intravenous administration of ampicillin was examined in experimental pneumococcal meningitis. Ampicillin was given at various dosages (3.25-62.5 mg/kg), and frequent samples of CSF were obtained for determination of concentrations of pneumococci and ampicillin. A long postantibiotic effect was observed in the CSF of all animals, and this effect consistently was longer than that observed in vitro.The question of the most effective mode of administration of (3-lactam antibiotics for treatment of severe bacterial infections is controversial. Commonly used regimens are largely empirical and are based on pharmacokinetic parameters (often only available from studies done with normal volunteers), knowledge of susceptibility characteristics of the suspected pathogen, and tradition. Parenteral therapy is preferred, but unpredictable absorption (e.g., shock) and clotting abnormalities may make the im route unreliable. Continuous iv administration produces a relatively fixed concentration of the antibiotic over time. Intermittent, or bolus, administration produces high initial con-

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Enhanced In Vitro Phagocytosis of Different Pathogens by Human Monocytes in the Presence of Antibiotics

Cited by 12 publications

References 20 publications

Differing mechanisms of surviving phagosomal stress among group BStreptococcusstrains of varying genotypes

Differing mechanisms of surviving phagosomal stress among group BStreptococcusstrains of varying genotypes

Effects of Doxycycline on the Phagocytosis of <sup>32</sup>P-Labelled <i>Escherichia coli</i> by Human Polymorphonuclear Cells

Intermittent or Continuous Therapy of Experimental Meningitis Due to Streptococcus pneumoniae in Rabbits: Preliminary Observations on the Postantibiotic Effect in Vivo

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